Drug interactions
Phentermine + Selegiline
Severity: Contraindicated
Phentermine and Selegiline: contraindicated interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Phentermine with MAO inhibitors can cause hypertensive crisis. Labeling contraindicates use during or within 14 days of MAOI treatment.
What this interaction means in plain words
Phentermine and Selegiline are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Phentermine belongs to Central Nervous System; Selegiline belongs to Central Nervous System.
Why it happens
Phentermine releases norepinephrine, and MAO inhibition blocks catecholamine breakdown, so pressor amines accumulate.
What to do
Avoid the combination and leave at least 14 days after stopping the MAOI. Choose a non-stimulant alternative.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Phentermine and Selegiline, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
Other interactions of Selegiline
- Amitriptyline + Selegiline Contraindicated
- Amoxapine + Selegiline Contraindicated
- Atomoxetine + Selegiline Contraindicated
- Benzphetamine + Selegiline Contraindicated
- Brimonidine + Selegiline Contraindicated
- Buprenorphine long-acting + Selegiline Contraindicated
Other interactions of Phentermine
- Isocarboxazid + Phentermine Contraindicated
- Linezolid + Phentermine Contraindicated
- Phenelzine + Phentermine Contraindicated
- Phentermine + Procarbazine Contraindicated
- Phentermine + Rasagiline Contraindicated
- Phentermine + Tranylcypromine Contraindicated
Frequently asked questions
Can I take Phentermine with Selegiline?
MediHelp rates the interaction as contraindicated. Phentermine and Selegiline are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Phentermine with MAO inhibitors can cause hypertensive crisis. Labeling contraindicates use during or within 14 days of MAOI treatment.
How serious is the interaction between Phentermine and Selegiline?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination and leave at least 14 days after stopping the MAOI. Choose a non-stimulant alternative.
What other medicines interact with Selegiline?
MediHelp also lists interactions of Selegiline with, for example, Amitriptyline, Amoxapine, Atomoxetine. The full list is on the Selegiline page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
